v0.25.3 - Provider-neutral model profile routing

v0.25.3 is a patch release that makes role and team-member model
routing portable across harnesses. Concrete provider/model descriptions
remain timestamped Artifact(kind=model-spec) deliverables, while
roles, actors, team members, and default assignments now bind to
provider-neutral Artifact(kind=model-profile) artifacts.

Added

• Added provider-neutral model-profile artifacts. processkit now
  ships nine Artifact(kind=model-profile) deliverables covering
  general, coding, research, writing, and governed routing profiles.
  Model-profile filenames deliberately avoid provider and model names;
  their content carries ranked candidate Artifact(kind=model-spec)
  references.
• Added model-profile schema support. Artifact schemas now recognize
  model-profile, binding schemas allow model-assignment targets to be
  either ModelProfile or ModelSpec artifacts, and role schemas expose
  default_model_profile while keeping legacy default_model
  compatibility.
• Added a model-profile migration helper.
  migrate_model_profiles.py creates the shipped profile artifacts and
  rewrites role/team-member model-assignment bindings from concrete
  model specs to profile targets.
• Added runtime provider access gates to the resolver. The resolver
  now expands model profiles into concrete model candidates only after
  applying runtime access constraints from user config, aibox.toml
  model providers, and native harnesses such as Codex, Claude, Gemini,
  Aider, Continue, Cursor, OpenCode, and Hermes.
• Added available_providers to model-recommender configuration.
  MCP callers can declare which providers are callable in the current
  environment without hard-coding a provider into role or team-member
  bindings.
• Added pk-doctor checks for routing portability. pk-doctor now
  flags provider/model names in model-profile filenames, missing profile
  candidate model specs, and Role/TeamMember bindings that directly pin a
  ModelSpec without conditions.direct_model_pin: true.

Changed

• Role and team-member bindings now target model profiles. Shipped
  default bindings, including Cora's default, no longer point directly to
  OpenAI, Anthropic, Google, or other concrete model artifacts.
• Concrete model specs remain provider/model named. The release keeps
  the v0.25.2 decision that ModelSpec artifacts map directly to
  provider/model families and therefore may include provider/model names
  in their filenames.
• Default binding documentation now describes two layers.
  Role/team-member defaults bind to profile artifacts; model profiles
  list provider-specific model-spec candidates; project overrides may
  still use direct ModelSpec pins when intentional.
• The release deliverable boundary accepts model-profile artifacts.
  scripts/check-src-context-drift.sh --release-deliverable now permits
  timestamped ModelProfile artifacts in src/context/artifacts/.
• Team and model-recommender docs now define harness portability.
  The docs make aibox responsible for surfacing runtime provider access,
  while processkit owns provider-neutral defaults and local fallback
  checks.

Removed

• Removed dogfood-specific provider bias/veto bindings from the
  deliverable. The old processkit-local Codex/OpenAI preference and
  Anthropic veto bindings no longer ship to derived projects.

Fixed

• Fixed Cora and role defaults under non-Codex harnesses. Changing
  aibox.toml from Codex to Claude, Gemini, OpenCode, Hermes, or another
  supported harness no longer leaves role/team-member defaults bound to a
  provider the harness cannot call.
• Fixed pk-doctor's blind spot around direct model pins. The doctor
  now distinguishes portable Role/TeamMember profile bindings from
  explicit direct model pins.
• Fixed resolver explanations for profile-expanded candidates.
  Resolved candidates now carry profile_id and profile_rank, making
  it visible which neutral profile produced the concrete model choice.

Verification

• pk-doctor --no-log passed with 0 ERROR / 0 WARN.
• scripts/check-src-context-drift.sh --release-deliverable passed.
• release_audit.py --tree=src-context passed with 0 ERROR / 0 WARN.
• 35 passed for resolver and default-binding coverage tests.
• 21 passed for model-recommender MCP filter tests.
• 20 passed for model migration tests.
• 26 passed for release-audit tests.
• uv run scripts/smoke-test-servers.py passed across the MCP smoke
  suite.

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