clean up migration-context comments

Comments should explain the code as it is, not narrate the change that produced
it. Drops "the old X" / "now" / "no longer" framing and a stale version pin in
favour of concrete names and the live constraints.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/state/session/__tests__/session-core-test.ts

@@ -32,12 +32,12 @@ jest.mock('#/analytics', () => ({
 }))
 
 /*
- * `configureModerationForAccount` is now fully synchronous (the labeler cache
+ * `configureModerationForAccount` is synchronous (the labeler cache is a local
- * is a local MMKV read), so it is no longer a prep await - but it still runs
+ * MMKV read), so it is not a prep await - but it still runs inside each factory
- * inside each factory with the freshly built bridge agent, before the awaited
+ * with the freshly built bridge agent, before the awaited prep steps. The
- * prep steps. The factory tests capture the agent with this mock, then inject a
+ * factory tests capture the agent with this mock, then inject a real refresh
- * real refresh into the awaited AA prefetch so a token rotation happens during
+ * into the awaited AA prefetch so a token rotation happens during prep, before
- * prep, before arm(). The default is a no-op so other tests are unaffected.
+ * arm(). The default is a no-op so other tests are unaffected.
  * (jest requires out-of-scope factory references to be `mock`-prefixed.)
  */
 const mockConfigureModerationForAccount =
@@ -553,10 +553,8 @@ function deriveRefreshedAccount(
 }
 
 /*
- * `PasswordSession` fires onUpdated with
+ * `PasswordSession` fires onUpdated with the fresh session BEFORE committing it
- * the fresh session BEFORE committing it internally, so the live getter is
+ * internally, so the live getter is still stale at hook time.
- * still stale at hook time. Driven through the real library (not a hand-rolled
- * fixture) so the ordering is authentic.
  */
 describe('session-hook payload threading (pre-commit ordering)', () => {
   it('delivers the NEW tokens via the payload even though the live getter is still pre-commit stale', async () => {
@@ -843,9 +841,9 @@ describe('refreshSession semantics', () => {
  * which is dead on the next cold start.
  *
  * We simulate the mid-prep rotation by capturing the bundle from the mocked
- * (now synchronous) `configureModerationForAccount` and making the mocked
+ * `configureModerationForAccount` and making the mocked
- * `prefetchAgeAssuranceServerData` (a genuine prep await in each factory) run
+ * `prefetchAgeAssuranceServerData` (a genuine prep await in each factory) run a
- * a real `session.refresh()`. The factory itself is re-required inside
+ * real `session.refresh()`. The factory itself is re-required inside
  * `jest.isolateModulesAsync` AFTER overriding `globalThis.fetch`, because
  * the network leaf captures `globalThis.fetch` at module load - and that
  * captured fetch is what PasswordSession's auto-refresh routes through.

src/state/session/__tests__/session-test.ts

@@ -1121,7 +1121,7 @@ describe('session', () => {
     expect(state.currentBundleState.did).toBe('bob-did')
 
     /*
-     * An 'update' from the stale (background) Alice bundle is now dropped
+     * An 'update' from the stale (background) Alice bundle is dropped
      * ENTIRELY - identical state object, no token write. A refresh completing
      * after switching away must not resurrect fresh tokens into the
      * switched-away account entry.

src/state/session/bridge-agent.ts

@@ -21,8 +21,8 @@ const UNSUPPORTED =
   'Not supported on PasswordSessionManager; use the session factories in session-core'
 
 /**
- * Convert live `PasswordSession` session data into the old `AtpSessionData`
+ * Convert live `PasswordSession` session data into the `AtpSessionData` shape
- * shape that `CredentialSession.session` consumers expect.
+ * that `CredentialSession.session` consumers expect.
  *
  * The only real adaptation is `active`: `AtpSessionData` requires it, while the
  * lexicon payload leaves it optional (absent means active, per the lexicon
@@ -59,8 +59,8 @@ function parseUrl(input: string): URL | undefined {
 /**
  * A `CredentialSession` whose auth core is a `PasswordSession`.
  *
- * This is the compat shim that lets the new session layer sit under the old
+ * This is the compat shim that lets a `PasswordSession` sit under `AtpAgent`:
- * `AtpAgent`: every call site that reads `agent.session`, `agent.pdsUrl`,
+ * every call site that reads `agent.session`, `agent.pdsUrl`,
  * `agent.dispatchUrl`, `agent.did` or calls `agent.resumeSession()` keeps
  * working, while the actual tokens, refresh serialization and PDS routing live
  * in the `PasswordSession` underneath.
@@ -111,9 +111,10 @@ export class PasswordSessionManager extends CredentialSession {
      * Why `defineProperty` and not `get session()` in the class body: the
      * parent declares `session` and `pdsUrl` as *properties*, and TypeScript
      * rejects overriding a property with an accessor (TS2611). Installing them
-     * at runtime sidesteps that, and it is safe because the parent's emitted
+     * at runtime sidesteps that, and it is safe as long as
-     * constructor never assigns either one - both are declaration-only in the
+     * `CredentialSession`'s emitted constructor does not assign either one
-     * 0.20.34 dist, so there is nothing to clobber and no ordering hazard.
+     * (both are declaration-only), so there is nothing to clobber and no
+     * ordering hazard.
      *
      * For the same reason this class must NOT redeclare `session`/`pdsUrl` as
      * fields: under `useDefineForClassFields` semantics (target esnext) a field
@@ -205,7 +206,7 @@ export class PasswordSessionManager extends CredentialSession {
 
   /*
    * `did`, `hasSession` and `dispatchUrl` are deliberately NOT overridden: the
-   * inherited getters read `this.session` / `this.pdsUrl`, which now resolve
+   * inherited getters read `this.session` / `this.pdsUrl`, which resolve
    * through the accessors above, so they are already live.
    */
 
@@ -214,21 +215,19 @@ export class PasswordSessionManager extends CredentialSession {
     init?: RequestInit,
   ): Promise<Response> {
     /*
-     * Absolutizing against `dispatchUrl` is what replaces the old
+     * Absolutizing against `dispatchUrl` routes to the stored PDS on the resume
-     * `sessionManager.pdsUrl = ...` writes and `_updateApiEndpoint`: it routes
+     * fast path and to the didDoc PDS from the first refresh onwards, since
-     * to the stored PDS on the resume fast path and to the didDoc PDS from the
+     * `PasswordSession` resolves an already absolute URL against its own base
-     * first refresh onwards, since `PasswordSession` resolves an already
+     * as a no-op.
-     * absolute URL against its own base as a no-op.
      */
     const target = new URL(url, this.dispatchUrl)
     const inner = this.#disposed ? null : this.#inner
 
     /*
      * A caller that set its own `authorization` header bypasses the inner
-     * session entirely. This preserves old `CredentialSession` semantics (it
+     * session entirely. This is mandatory: `PasswordSession.fetchHandler`
-     * skipped its own bearer in that case) and is mandatory here:
+     * throws `TypeError` on a pre-set authorization header rather than
-     * `PasswordSession.fetchHandler` throws `TypeError` on a pre-set
+     * deferring to it.
-     * authorization header rather than deferring to it.
      */
     if (
       !inner ||
@@ -252,9 +251,9 @@ export class PasswordSessionManager extends CredentialSession {
     }
     const data = await inner.refresh()
     /*
-     * Re-shape the lex payload into the old XRPC envelope. `headers` is empty
+     * Re-shape the lex payload into the `@atproto/api` XRPC response envelope.
-     * because the inner session does not surface response headers, and no
+     * `headers` is empty because the inner session does not surface response
-     * caller in this app reads them off a refresh.
+     * headers, and no caller in this app reads them off a refresh.
      */
     return {
       success: true,

src/state/session/create-account.ts

@@ -123,8 +123,6 @@ export async function createSessionBundleAndCreateAccount(
     })
   }
 
-  // Proxy-header ordering matches the old agent factories: after the void-fired
-  // post-signup writes are started, before the prep await.
   bundle.agent.configureProxy(BLUESKY_PROXY_HEADER.get())
 
   await Promise.all([gates, aa])
@@ -138,10 +136,9 @@ export async function createSessionBundleAndCreateAccount(
  * Snapshot a just-created session as a `SessionAccount`.
  *
  * `com.atproto.server.createAccount` returns only tokens, handle, did and
- * didDoc, so the lex session carries no email state or `active` flag until the
+ * didDoc, so the session carries no email state or `active` flag until the
- * first refresh. The old `CredentialSession.createAccount` synthesized those
+ * first refresh. Synthesize those fields from the creation input so the
- * fields from the creation input; do the same here so the persisted account
+ * persisted account does not briefly claim the email is unknown.
- * does not briefly claim the email is unknown.
  */
 function snapshotNewAccount(
   session: PasswordSession,

src/state/session/session-core.ts

@@ -223,9 +223,8 @@ export async function createSessionBundleAndResume(
   const aa = prefetchAgeAssuranceServerData({agent: bundle.agent})
 
   /*
-   * Proxy-header ordering matches the old agent factories: the header is
+   * The proxy header is applied after the PDS-targeting setup above, so those
-   * applied after the age-assurance prefetch starts and before the prep await,
+   * calls run without it.
-   * so the PDS-targeting setup calls above run without it.
    */
   bundle.agent.configureProxy(BLUESKY_PROXY_HEADER.get())
 
@@ -285,7 +284,6 @@ export async function createSessionBundleAndLogin(
   configureModerationForAccount(bundle.agent, earlyAccount)
   const aa = prefetchAgeAssuranceServerData({agent: bundle.agent})
 
-  // Proxy-header ordering matches the old agent factories.
   bundle.agent.configureProxy(BLUESKY_PROXY_HEADER.get())
 
   await Promise.all([gates, aa])