fix: terminal UTF-8, deploy --no-otel, hermes schema drift, opencode model carry

[dgokeeffe]

Related issue

N/A — no tracking issue yet. (Replace with Closes #NNN if one exists.)

Summary

Four small, independent backend fixes bundled for review:

• Terminal UTF-8 locale (omnigent/inner/terminal.py) — when the inherited environment carries no UTF-8 locale signal, force C.UTF-8 into the terminal env so native TUI harnesses in minimal containers don't fall back to ASCII (glibc/musl ship C.UTF-8 without a locale archive).
• --no-otel deploy (deploy/databricks/deploy.py, databricks.yml, README.md) — deploy without the OpenTelemetry collector for collector-less workspaces. Also makes the post-start UC USE_CATALOG/USE_SCHEMA grant step warn-and-continue instead of aborting the whole deploy when the grant fails (the SP may already have access via group inheritance, or the deployer may lack MANAGE on a shared catalog).
• Hermes schema drift (omnigent/hermes_native_forwarder.py) — introspect state.db columns and adapt SELECTs, so a schema change across Hermes builds (e.g. a dropped sessions.cwd) no longer aborts discovery/mirroring with no such column.
• opencode model carry (omnigent/opencode_native_provider.py) — carry the user config's top-level model default into the synthesized config when no model is pinned, so opencode-native doesn't silently fall back to its own default over the merged models map.

ELI5

• Terminal fix: some containers start with no UTF-8 locale set, so special characters break in the TUI; we now set a safe UTF-8 locale automatically.
• --no-otel: you can now skip the telemetry collector if you don't want it.
• Hermes fix: Hermes changes its internal database layout between versions; we now read the layout at runtime instead of guessing, so mirroring keeps working.
• opencode fix: when you set a default model in your config, that choice now survives into opencode sessions instead of being overridden.

Test Plan

• Lint: ruff check + ruff format clean on all changed Python; byte-compile clean.
• Updated unit tests pass: tests/inner/test_terminal.py (UTF-8 locale fallback), tests/test_hermes_native_forwarder.py (schema introspection), tests/test_opencode_native_provider.py (model carry-over).
• Full suite left to CI (the complete suite can't be run in this offline environment).

Demo

N/A — non-visual changes. --no-otel is a CLI flag; optionally show omnigent deploy ... --no-otel resulting in a collector-less deployment.

Type of change

• Bug fix
• Feature
• UI / frontend change
• Refactor / chore
• Docs
• Test / CI
• Breaking change

Test coverage

• Unit tests added / updated
• Integration tests added / updated
• E2E tests added / updated
• Manual verification completed
• Existing tests cover this change
• Not applicable

Coverage notes

Each fix has a corresponding updated unit test (test_terminal.py, test_hermes_native_forwarder.py, test_opencode_native_provider.py). The --no-otel deploy path is covered by the updated deploy option wiring + docs; an integration deploy test would be a nice follow-up but isn't included here. These four changes are independent of each other and of the host-sharing PR — happy to split into separate PRs if reviewers prefer one-fix-per-PR.

Changelog

--no-otel deploys without the OpenTelemetry collector; terminal auto-forces a UTF-8 locale in minimal containers

[github-actions]

@dgokeeffe This PR is a Bug fix, Feature, or UI / frontend change but the Demo section is missing or only contains a placeholder.

These change types require a screenshot or screen recording so reviewers can see the new behaviour without checking out the branch. Please update the Demo section with:

• A screenshot or screen recording of the change, or
• A link to a hosted video or GIF showing the new behaviour.

Use N/A only when the change has no user-visible effect whatsoever (e.g. a pure refactor or test-only change). If that's the case, uncheck the relevant type box and check Refactor / chore or Test / CI instead.

[PattaraS]

Thanks for working through these fixes. Could you please split this into separate PRs for:

1. terminal UTF-8/locale handling
2. Databricks deploy --no-otel
3. Hermes schema drift
4. OpenCode model carry-over

These changes address unrelated problems, touch different subsystems, and have different verification and rollback paths. Keeping them separate will make each fix easier to validate, review, and merge independently.

Please link the resulting PRs here when they are ready.

[dgokeeffe]

Split into 4 separate PRs as requested:

• terminal UTF-8 locale
• deploy --no-otel + UC grant resilience
• Hermes schema drift
• opencode model carry

Links to the new PRs above. Closing this one.