Add migration docs and fix notarization scripts to use inline credentials

Keychain profile approach doesn't work from Galaxy terminal (no interactive
auth entitlement). Switched to inline Apple ID/team/password in notarize.sh
and package.sh. Added migration-docs/ for session continuity on new machines.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

migration-docs/session-history-may.md

@@ -0,0 +1,48 @@
+# Prior Session — 2026-05-13 / 2026-05-14
+
+## Tasks Completed
+
+1. **Codebase learn** — Full read of the Galaxy codebase (56-crate Rust workspace, fork of Warp with Bedrock AI)
+2. **Code signing pipeline** — Created complete macOS signing, notarization, and DMG packaging workflow
+3. **Review & hardening** — Two rounds of adversarial review + fixes applied
+4. **Documentation** — Updated GALAXY.md with signing/diagnostics docs
+5. **Code review** — Started adversarial review of last day's committed changes
+
+## Key Decisions
+
+- **Entitlements:** `network.client` + `automation.apple-events` + `cs.allow-unsigned-executable-memory` (for Metal/wgpu shader compilation under hardened runtime)
+- **Signing approach:** Simple standalone scripts (sign.sh, notarize.sh, package.sh) rather than adapting Warp's 800-line CI bundle script
+- **Signing method:** Inside-out (binary first, then bundle) with `--timestamp` on all codesign calls
+- **Architecture:** arm64 only (no universal binary needed)
+- **Bundle ID:** `com.samsung.Galaxy`
+- **Certificate:** `Developer ID Application: SAMSUNG ELECTRONICS AMERICA, INC. (3JU72Z7Y3J)`
+
+## Files Created
+
+- `BuildSupport/Galaxy.entitlements` — macOS entitlements for code signing
+- `sign.sh` — Code signs Galaxy.app with Samsung Developer ID cert + hardened runtime
+- `notarize.sh` — Submits to Apple notary service + staples ticket
+- `package.sh` — Creates DMG + signs + notarizes + staples
+- `build-debug.sh` — Full pipeline orchestration (debug)
+- `build-release.sh` — Full pipeline orchestration (release)
+- `copy-dmgs.sh` — Copies DMGs to ~/Downloads with date+letter suffix
+- `GALAXY.md` — Updated with signing pipeline + diagnostics documentation
+
+## Code Review Findings (STILL OPEN)
+
+### High Severity
+1. **[Security] `dump_error_snapshot` writes full conversation context to world-readable files** — Error dumps include user's shell command outputs, secrets potentially in conversation. Recommendation: gate behind `GALAXY_BEDROCK_DIAGNOSTICS=1` or set 0600 permissions.
+2. **[Security] `error_dump_directory` uses compile-time `CARGO_MANIFEST_DIR`** — Points to build machine path in release builds. Should be gated behind `cfg!(debug_assertions)`.
+3. **[Security] Install script fetches Homebrew/rustup from HEAD without pinning** — Supply chain risk in curl-pipe-bash context.
+
+### Medium Severity
+4. **[Robustness] Silent mutex poisoning in `dump_error_snapshot`** — Partial data written without indication.
+5. **[Performance] Captured lines buffer unbounded by bytes** — Single "line" can be several MB for large contexts.
+6. **[Correctness] `is_retryable` uses fragile string matching** — `"Validation error"` may not appear in stream errors.
+7. **[Correctness] `rotate_if_needed` double-renames** — Off-by-one: current file renamed twice (harmless but confused logic).
+8. **[Robustness] `read_file_tail` blocks async runtime** — 200KB sync I/O per file on potentially slow filesystem.
+
+### Low Severity
+9. Integer overflow in token sum cast to u32
+10. Race condition in install script's pkill → rm -rf sequence
+11. `git pull --ff-only` fails silently on diverged branches