docs: sync authority blueprints and update repository description

[DTALEX66]

Scope

Pull the CODEX-frozen execution blueprint, mandatory addenda, and truth/handoff docs into main, and update the repository description files (README + PROJECT_STATUS) to reference them as the authoritative task definition source.

Included

• docs/truth/ — FROZEN_EXECUTION_BASELINE, EXECUTION_STATUS_LOG, AUTHORITY_CONTRACT, CURRENT_STATE_TRUTH, H0_H1_STATUS_HANDOFF (+ SHA files)
• docs/taskpacks/ — DEEPSEEK_FULL_EXECUTION_TASKPACK, WEB + KLC addenda (+ SHA files)
• README.md — new "冻结执行基线（权威任务包）" section linking the authority docs
• docs/PROJECT_STATUS.md — new "冻结执行基线（权威蓝图与增补）" section

Truthfulness

• H0 (v0.5.1) is merged on main; H1 backend is in PR H1 batch: GOV-001, AXW-020R/020A/020B/020C #72, not yet merged — README/PROJECT_STATUS explicitly state that product capability prose reflects main's actual state, and that the H1 backend is not yet merged.
• Historical docs/FUTURE_EXECUTION_BLUEPRINT.md remains as migration input; authority order is documented in AUTHORITY_CONTRACT.md.
• SHA files verified to match their .md content.

Verification

• check_repository_conventions.py PASS; git diff --check PASS.
• All 7 cross-referenced authority links resolve to files present in this PR.

Excluded

• No merge authorization requested here; this is a docs-sync PR only.
• H1 backend code is not part of this PR (separate PR H1 batch: GOV-001, AXW-020R/020A/020B/020C #72).