Align docs terminology and runtime file references with current architecture

[Copilot]

The docs had drifted from the codebase: several runtime terms and file references no longer matched current implementation names. This PR updates core documentation pages in docs/ so architecture and runtime docs describe the system as it exists today.

• Terminology alignment

  • Standardized wording toward current runtime naming (notably Constraint Evaluation runtime and CheckpointReview-focused phrasing).
  • Reduced ambiguous legacy wording in tour summaries.

• Architecture reference corrections

  • Updated runtime layer key-file references in docs/ARCHITECTURE.md to current source files (reality-projection*, constraint-evaluation*, state-snapshot).
  • Clarified naming continuity for context state (Context Snapshot, formerly Context Capsule).

• Reality runtime doc synchronization

  • Replaced stale projection/constraint file references in docs/reality-runtime.md with current core/server paths.
  • Kept conceptual flow intact while fixing implementation pointers.

Example of the reference updates:

- `syncpoint-core/src/projection.ts`
+ `syncpoint-core/src/reality-projection.ts`

- `syncpoint-core/src/constraint-runtime.ts`
+ `syncpoint-core/src/constraint-evaluation.ts`