feat(web,hub): export session conversation

[swear01]

Closes #793

Summary

• Add HapiSessionExport v1 shared schema/types and a guarded GET /api/sessions/:id/export hub endpoint.
• Export chronological visible messages with queued/hidden rows omitted and a 20,000-message hard cap returning 413.
• Add web header export action with JSON/Markdown dialog, persisted format preference, AbortController support, and Blob download.
• Generate Markdown from the same export payload via normalizeDecryptedMessage with concise tool summaries.

Test plan

• bun typecheck
• bun run --cwd hub test src/web/routes/sessions.test.ts src/sync/messageService.test.ts --bail=1
• bun run --cwd web test src/lib/sessionExport/markdown.test.ts --run
• bun run test:hub
• bun run test:web
• bun run test:shared
• bun run --cwd cli test src/claude/claudeRemote.test.ts --run (rerun after unrelated CLI timeout flake)

Note: A later full bun typecheck && bun run test attempt was interrupted/ignored at user request after hitting an unrelated CLI timeout flake in src/claude/claudeRemote.seam.test.ts; this PR does not touch CLI code.

Manual verification

• Started isolated source env from branch fix/issue-793-session-export on port 43006.
• User confirmed export behavior looked good.
• Isolated env stopped before PR creation.

[github-actions]

Findings

• [Major] Export can reorder invoked scheduled messages — getAllMessages() reads by insertion seq, but scheduled local messages are inserted when queued and get invokedAt only when released/consumed. Once such a message is invoked, this export includes it at its old insertion position, while the visible thread pagination orders by COALESCE(invoked_at, created_at), seq; JSON/Markdown exports can therefore disagree with the visible conversation chronology. Evidence hub/src/sync/messageService.ts:99, related context hub/src/store/messages.ts:221.
  Suggested fix:

  const messages = this.store.messages.getAllMessages(sessionId)
      .filter(isExportVisibleStoredMessage)
      .sort((a, b) => {
          const aAt = a.invokedAt ?? a.createdAt
          const bAt = b.invokedAt ?? b.createdAt
          return aAt !== bAt ? aAt - bAt : a.seq - b.seq
      })
      .map(toDecryptedMessage)

Summary

• Review mode: initial
• One issue found: export ordering can diverge from the visible chat for scheduled messages after they are invoked.

Testing

• Not run (automation). Add a hub test where a scheduled message is inserted first, a normal message is inserted second, then the scheduled message is marked invoked later; export should order by invoked/display time.

HAPI Bot

[github-actions]

[MAJOR] getAllMessages() returns rows by insertion seq, but scheduled local messages are inserted when queued and receive invokedAt later. After release/consume, this export includes them at their old insertion position, unlike the visible thread which orders by COALESCE(invoked_at, created_at), seq. That makes JSON/Markdown exports disagree with the visible chronology.

Suggested fix:

const messages = this.store.messages.getAllMessages(sessionId)
    .filter(isExportVisibleStoredMessage)
    .sort((a, b) => {
        const aAt = a.invokedAt ?? a.createdAt
        const bAt = b.invokedAt ?? b.createdAt
        return aAt !== bAt ? aAt - bAt : a.seq - b.seq
    })
    .map(toDecryptedMessage)

[github-actions]

Findings

• [Minor] Markdown front matter can be broken by session metadata containing newlines — escapeYamlString() only escapes backslashes and quotes, but metadata.name, metadata.path, and metadata.host are user/session-controlled strings that can contain \n/\r. When those values are interpolated into quoted YAML scalars, a newline can terminate the field and inject extra front matter keys or produce invalid Markdown metadata. Evidence web/src/lib/sessionExport/markdown.ts:18.
  Suggested fix:

  function escapeYamlString(value: string): string {
      return value
          .replace(/\\/g, '\\\\')
          .replace(/"/g, '\\"')
          .replace(/\r/g, '\\r')
          .replace(/\n/g, '\\n')
  }

Summary

• Review mode: follow-up after new commits
• One minor issue found in Markdown export front matter escaping. Prior bot finding about scheduled-message export ordering appears addressed by the new sort and regression test.

Testing

• Not run (automation): bun is not installed in this runner (/bin/bash: bun: command not found). Add a markdown export test with a session title containing a newline and quote.

HAPI Bot

[github-actions]

[MINOR] Markdown front matter can be broken by session metadata containing newlines. escapeYamlString() only escapes backslashes and quotes, but metadata.name, metadata.path, and metadata.host are user/session-controlled strings that can contain \n/\r; interpolating those into quoted YAML scalars can terminate the field and inject extra front matter keys or produce invalid metadata.

Suggested fix:

function escapeYamlString(value: string): string {
    return value
        .replace(/\\/g, '\\\\')
        .replace(/"/g, '\\"')
        .replace(/\r/g, '\\r')
        .replace(/\n/g, '\\n')
}

[github-actions]

Findings
None.

Questions
None.

Summary
Review mode: follow-up after new commits
No issues found in the latest full diff. The previous front-matter escaping finding is addressed in current head with CR/LF escaping and a regression test. Residual risk: download dialog behavior, AbortController cancellation, and persisted format preference are source-reviewed/unit-reviewed only; no browser-level export flow test found in repo/docs.

Testing
Not run (automation): bun is not installed in this runner (/bin/bash: bun: command not found).

HAPI Bot