Add comprehensive tests for Python Agent Mail adapter

- Add 24 new tests across 6 test classes
- Cover authorization headers, request body validation
- Test reservation edge cases (TTL, special chars, multiple reservations)
- Test timeout configuration and precedence
- Test inbox/notification edge cases (large payloads, Unicode, nested data)
- Fix timeout parameter precedence bug (constructor now overrides env var)
- All 51 tests pass

Closes bd-b134

Amp-Thread-ID: https://ampcode.com/threads/T-2f39e97d-38de-4df4-bf94-ef90184cee8a
Co-authored-by: Amp <amp@ampcode.com>

.beads/beads.jsonl

@@ -194,7 +194,7 @@
 {"id":"bd-aysr","content_hash":"f8ff127568f471cc42391b1287cce69b376fb1b49bbef20a24d3394f57fba066","title":"Test numeric 1","description":"","status":"closed","priority":1,"issue_type":"task","created_at":"2025-11-05T12:58:41.498034-08:00","updated_at":"2025-11-05T12:58:44.73082-08:00","closed_at":"2025-11-05T12:58:44.73082-08:00","source_repo":"."}
 {"id":"bd-azqv","content_hash":"b4e68adcec7b19f567ebee47f505ca6b529c17b4c4b885282cfc564e8a874f9f","title":"Ready issue","description":"","status":"closed","priority":1,"issue_type":"task","created_at":"2025-11-07T19:04:22.247039-08:00","updated_at":"2025-11-07T22:07:17.344986-08:00","closed_at":"2025-11-07T21:55:09.429024-08:00","source_repo":"."}
 {"id":"bd-b121","content_hash":"5d71e793a6de110be977bf87cfd25c3b461f452a1e8e44633452de1f8343a098","title":"Fix :memory: database connection pool issue causing \"no such table\" errors","description":"Critical bug in v0.21.6 where :memory: databases with cache=shared create multiple connections in the pool, causing intermittent \"no such table\" errors. SQLite's shared cache for in-memory databases only works reliably with a single connection.\n\nRoot cause: Missing db.SetMaxOpenConns(1) after sql.Open() for :memory: databases.\n\nImpact: 37 test failures in VC project, affects all consumers using :memory: for testing.","acceptance_criteria":"- Add db.SetMaxOpenConns(1) for :memory: databases only\n- Verify VC test suite passes (37 previously failing tests)\n- Add a test in Beads that reproduces the issue\n- Document the pool limitation in code comments\n- Release as Beads v0.21.7","status":"closed","priority":0,"issue_type":"bug","created_at":"2025-11-04T00:52:56.318619-08:00","updated_at":"2025-11-05T11:31:27.50439-08:00","closed_at":"2025-11-05T00:50:00.558124-08:00","source_repo":"."}
-{"id":"bd-b134","content_hash":"87166a251a1e2459cbc2538769bea4e3f6a9f6c96aae174c7fcb0099f0de0085","title":"Add tests for Integration Layer Implementation","description":"While implementing bd-wfmw, noticed missing tests","status":"open","priority":1,"issue_type":"task","created_at":"2025-11-08T00:20:30.804172-08:00","updated_at":"2025-11-08T00:20:30.804172-08:00","source_repo":".","dependencies":[{"issue_id":"bd-b134","depends_on_id":"bd-wfmw","type":"discovered-from","created_at":"2025-11-08T00:20:30.850776-08:00","created_by":"daemon"}]}
+{"id":"bd-b134","content_hash":"d291c43cce23793342ead99e03001af26af559f589be271dfb2723c9a077bb97","title":"Add tests for Integration Layer Implementation","description":"While implementing bd-wfmw, noticed missing tests","notes":"Reviewed existing coverage:\n- Basic test coverage exists in lib/test_beads_mail_adapter.py\n- Integration tests cover failure scenarios in tests/integration/test_mail_failures.py\n- Good coverage of: enabled/disabled modes, graceful degradation, 409 conflicts, HTTP errors, config\n- Missing: authorization headers detail, request body structure validation, concurrent reservation timing, TTL edge cases","status":"closed","priority":1,"issue_type":"task","created_at":"2025-11-08T00:20:30.804172-08:00","updated_at":"2025-11-08T02:17:04.046571-08:00","closed_at":"2025-11-08T02:17:04.046571-08:00","source_repo":".","dependencies":[{"issue_id":"bd-b134","depends_on_id":"bd-wfmw","type":"discovered-from","created_at":"2025-11-08T00:20:30.850776-08:00","created_by":"daemon"}]}
 {"id":"bd-b245","content_hash":"5ad06a3b7126d4a4eb779cd01319cc4541869f4295afcf6f91cf7d6d36078cb0","title":"Add migration registry and simplify New()","description":"Create migrations.go with Migration type and registry. Change New() to: openDB -\u003e initSchema -\u003e RunMigrations(db). This removes 8+ separate migrate functions from New().","status":"closed","priority":1,"issue_type":"task","created_at":"2025-11-01T11:41:14.862623-07:00","updated_at":"2025-11-02T12:55:59.954845-08:00","closed_at":"2025-11-02T12:55:59.954854-08:00","source_repo":"."}
 {"id":"bd-b47c034e","content_hash":"1e8e5ae6388d6546f55421886bd88e7acd2fdade1052d2d7d1b193276777c05d","title":"Address gosec security warnings (102 issues)","description":"Security linter warnings: file permissions (0755 should be 0750), G304 file inclusion via variable, G204 subprocess launches. Many are false positives but should be reviewed.","design":"Review each gosec warning. Add exclusions for legitimate cases to .golangci.yml. Fix real security issues (overly permissive file modes).","status":"closed","priority":2,"issue_type":"task","created_at":"2025-10-25T13:47:10.719134-07:00","updated_at":"2025-11-04T11:10:23.533333-08:00","closed_at":"2025-11-04T11:10:23.533338-08:00","source_repo":"."}
 {"id":"bd-b4b0","content_hash":"ab3833b7a2cd79e39cbf6e41e35da88c8c45581dff3862bad2b8476b37c3b494","title":"Implement fs bridge layer for WASM (Go syscall/js to Node.js fs)","description":"Go's os package in WASM returns 'not implemented on js' for mkdir and other file operations. Need to create a bridge layer that:\n\n1. Detects WASM environment (GOOS=js)\n2. Uses syscall/js to call Node.js fs module functions\n3. Implements wrappers for:\n   - os.MkdirAll\n   - os.ReadFile / os.WriteFile\n   - os.Open / os.Create\n   - os.Stat / os.Lstat\n   - filepath operations\n   \nApproach:\n- Create internal/wasm/fs_bridge.go with //go:build js \u0026\u0026 wasm\n- Export Node.js fs functions to Go using global.readFileSync, global.writeFileSync, etc.\n- Wrap in Go API that matches os package signatures\n- Update beads.go and storage layer to use bridge when in WASM\n\nThis unblocks bd-4462 (basic WASM testing) and [deleted:bd-5bbf] (feature parity testing).","status":"closed","priority":1,"issue_type":"task","created_at":"2025-11-02T22:22:42.796412-08:00","updated_at":"2025-11-03T22:16:38.855334-08:00","closed_at":"2025-11-02T22:47:49.586218-08:00","source_repo":".","dependencies":[{"issue_id":"bd-b4b0","depends_on_id":"bd-44d0","type":"parent-child","created_at":"2025-11-02T22:23:49.585675-08:00","created_by":"stevey"}]}