Prepare 0.8.1 context and team workflow improvements

[theDakshJaitly]

MEX 0.8.1 makes repository knowledge and team handoffs easier to use while preserving explicit approval, checkout-local drafts, and Git-based sharing.

• Show project knowledge in an interactive Context graph, with recorded relationships, direct code groundings, and retained list/detail views.
• Let Inbox propose additions and corrections to existing knowledge. Add open-to-team Relays, simpler local drafting, and member reactivation.
• Require explicit grounding baseline acceptance. Add checkout-local logging preferences and bounded retrieval of relevant historical notes.
• Correct Wiki migration/provenance/retry behavior and harden Windows byte and file-identity handling. Canonical Team records retain portable revisions; Wiki/local records retain exact bytes. Ownership checks retain full-width IDs and preserve foreign replacements during failure and recovery.

Verification on 35bfc075888706d6b105b39b0d711ff7a588b551 (CI run 34238595434):

• Windows Server 2022: all 337 tests across 17 storage suites, production build, and packed Hub/official-skills install smoke pass.
• macOS 14: storage suites, build, and packed-install smoke pass.
• Node 22.22.0 and 24: full checks pass. Node 22 records 3,354 passing root tests, one platform-specific skip, 85 evaluator tests, build, and package/Graph CLI smokes.
• Hub browser checks pass, including the corrected Context/Relay assertions.

Capabilities goldens remain byte-exact across Git checkout conversion. Replacement tests preserve exact conflict assertions and foreign files. The one real Inbox integration file has a 30-second Windows-only hang guard for observed runner variability; other files/platforms and production/performance bounds are unchanged.

This remains a draft release. The release-performance gate fails on missing Settings heap budgets for all three fixture sizes. Other first-pass runtime crossings remain unconfirmed because that immediate failure suppresses confirmation; existing budgets are preserved. Settings calibration/performance review and the separate final telemetry phase remain pending. Detailed scope and evidence: docs/design/0.8.1-release-plan.md.