perf(daemon): add constrained ARM edge runtime

[aaf2tbz]

Summary

Adds a documented source/Bun edge runtime profile for constrained 64-bit ARM devices, with Raspberry Pi 3B+ as the minimum target. The profile removes eager idle work, switches the built-in native embedding default to MiniLM/384d, honors configured native model settings, and process-isolates the native runtime so its RSS is reclaimed after 30 seconds idle.

Closes #921.

Changes

• Add an approved edge-runtime spec, dependency index entry, operator guide, and Linux /proc RSS/query-embedding gate.
• Default native embeddings to Xenova/all-MiniLM-L6-v2/384d and migrate only the exact legacy native default; custom models/providers remain unchanged.
• Propagate validated native model/dimension config into the worker and terminate an edge-only child process after the idle window.
• Keep the edge daemon lazy at idle: fixed-file polling, no startup embedding probe, no pre-spawned synthesis/extraction helper, lazy tokenizer/provider catalogs, and lazy UMAP/Louvain routes.
• Centralize embedding defaults across core, daemon, setup/configure flows, templates, and docs.

Type

• feat — new user-facing feature (bumps minor)
• fix — bug fix
• refactor — restructure without behavior change
• chore — build, deps, config, docs
• perf — performance improvement
• test — test coverage

Packages affected

• @signet/core
• @signet/daemon
• @signet/cli / dashboard
• @signet/sdk
• @signet/connector-*
• @signet/web
• predictor
• Other: docs and edge verification script

Screenshots

N/A — no UI changes.

PR Readiness (MANDATORY)

• Spec alignment validated (INDEX.md + dependencies.yaml)
• Agent scoping verified on all new/changed data queries
• Input/config validation and bounds checks added
• Error handling and fallback paths tested (no silent swallow)
• Security checks applied to admin/mutation endpoints
• Docs updated for API/spec/status changes
• Regression tests added for each bug fix
• Lint/typecheck/tests pass locally

Readiness notes:

• bun scripts/spec-deps-check.ts passes with 87 indexed specs.
• No new data query or mutation/admin endpoint was added. Existing memory-route scope/auth behavior is unchanged and its isolated scope/auth suites pass.
• Runtime profile values, embedding dimensions (1–65,536), and model identifier length are bounded. Invalid values fall back with diagnostics.
• Changed-file validation is green. Repository-wide lint/typecheck/test failures are existing origin/main baseline failures, detailed below.

Migration Notes (if applicable)

• Migration is idempotent
• Daemon Rust parity reviewed or explicitly N/A
• Rollback / compatibility note included in PR description

Config migration v5 is idempotent and changes only native/local configs using the exact legacy Nomic default with absent/768 dimensions. Custom native models/dimensions and external providers are preserved. Source memories are not deleted; the existing tracker re-embeds model/dimension mismatches. Rust parity is N/A because no route surface was added or removed. Rolling back retains valid 384d config/data; operators may explicitly restore the old model/dimensions if desired.

Testing

• bun test passes
• bun run typecheck passes
• bun run lint passes
• Tested against running daemon
• N/A

Validation:

• 157/157 focused tests pass across runtime profile, polling, native embeddings, process selection/idle shutdown, migration, config, tracker, OAuth/router, and tokenizer budgeting.
• All other adjacent suites pass when run one file per process: daemon auth/CORS/status/refactor, config migration, memory lineage/routes/scoping/curator, skill reconciler, and CLI setup validation/pipeline/plugins/protection/shared.
• The native event-loop isolation E2E passes in the repository-wide run.
• Core, daemon, CLI, and self-contained native Bun builds pass.
• Source and built edge daemons were exercised with the real cached MiniLM model: 384d status succeeds, the daemon remains responsive, the embedding child exits after 30 seconds idle, and no child leaks remain after shutdown.
• Full bun test: 3,301 pass / 47 skip. The monolithic run has existing cross-suite/global-state and fixture failures. The two isolated adjacent failures reproduce exactly on untouched origin/main: inference-api.test.ts is 14 pass / 12 fail and setup.test.ts is 17 pass / 1 fail.
• Full daemon typecheck reports exactly the same 421 errors on this branch and untouched origin/main; no new changed-line error is introduced. @signet/core typecheck passes.
• Changed-file Biome passes with one pre-existing warning. Full lint reports 1,839 errors here versus 1,840 on untouched origin/main.

AI disclosure

• No AI tools were used in this PR
• AI tools were used (see Assisted-by tags in commits)

Notes

This is intentionally a draft until the documented release gate is run on physical Raspberry Pi 3B+ hardware. macOS development measurements validate lazy loading and process reclamation but do not substitute for the required Linux ARM result: idle daemon RSS below 100 MiB and a warm query embedding below five seconds.

The constrained path intentionally uses the source/Bun daemon. The self-contained native binary remains the standard portable/offline distribution and continues to embed its release assets.