upgrade 2.0 phase 1

[yifanxuaaa]

• feat(layerstack): add baseline route observability
• feat(workspace): scope execution scratch to sessions
• feat(layerstack): add portable root contract
• chore(layerstack): remove stale guidance and artifacts
• feat(layerstack): implement incremental publication
• feat(layerstack): implement candidate materialization
• fix(layerstack): stabilize candidate session I/O
• perf: parallelize contiguous candidate writes
• perf: streamline candidate carrier durability
• feat(layerstack): complete materialization GC alignment
• feat(mpla-poc): freeze M0 scaffold interfaces
• feat(mpla-poc): implement stationary sealing core
• feat(mpla-poc): add durable allocation ownership
• feat(mpla-poc): qualify stationary overlay environment
• test(mpla-poc): add physical M0 falsifiers
• fix(mpla-poc): reap adopted process trees
• feat(mpla-poc): freeze M1 shared contract
• feat(mpla-poc): add activation and resource controls
• feat(mpla-poc): seal and verify evidence manifests
• feat(mpla-poc): add deterministic fixture generator
• Add matched current I2 controls
• Implement durable locator ref recovery
• Enforce locator parent preconditions
• feat(mpla-poc): add bounded semantic builder and oracle
• feat(mpla-poc): add smoke lifecycle dispatcher
• feat(mpla-poc): add authenticated receipt-hit sealing
• Add bounded affected-path receipt scanner
• Add measured M1 smoke campaign
• Persist bound product catalog evidence
• Create semantic spool parent for smoke campaign
• Fix smoke overlay lower layers
• Use permanent payload allocation arena in smoke suite
• Fix M1 cgroup isolation and semantic object fanout
• feat(mpla-poc): freeze M2 checkpoint
• feat(mpla-poc): add M2 promotion and locator replacement
• feat(mpla-poc): add overload crash and evacuation coverage
• test(mpla-poc): add M2 heavy scale harness
• test(mpla-poc): add lead heavy campaign dispatch
• test(mpla-poc): record M2 public runtime envelope
• mpla: freeze M2R corrective interface
• mpla: bind storage authority to public session
• mpla: package scoped storage administrator
• feat(mpla): add scoped storage admin authority
• fix(mpla): wire HV-07 durable operation edges
• fix(mpla): bind storage authority to public runtime
• docs: improve SEO and GEO discovery