fix: resolve the OpenClaw state dir consistently (md-mirror workspace map, CLI and workspace defaults)

[gorkem2020]

Problem

The plugin assumed a single OpenClaw instance living at ~/.openclaw:

• resolveAgentWorkspaceMap (md-mirror) only read the legacy agents.list array. OpenClaw 2026.9 writes the keyed agents.entries form, so the mirror logged mdMirror: no agent workspaces found and wrote every agent's mirror into the default directory.
• When the runtime config carried no agents, the fallback read ~/.openclaw/openclaw.json. On a host running a second instance (OPENCLAW_STATE_DIR pointing elsewhere) that is another instance's config; the observed effect was the second instance's mirror landing inside the first instance's main-agent workspace.
• The default db, workspace and md-mirror directories, the CLI --openclaw-home default and OAuth file path, and the workspace capability default were all rooted at homedir()/.openclaw regardless of OPENCLAW_STATE_DIR.

Change

• src/openclaw-paths.ts: one resolver. State dir = OPENCLAW_STATE_DIR, then OPENCLAW_HOME, then ~/.openclaw; config path = OPENCLAW_CONFIG_PATH, then <state dir>/openclaw.json. Blank or whitespace-only values count as unset.
• The md-mirror workspace map reads both agents.entries (keyed) and agents.list (array), from the runtime config first and from the resolved config file second.
• Plugin defaults, the CLI and the workspace capability default all go through the resolver. Single-instance installs resolve to exactly the same paths as before, so there is no behaviour change for the default layout.

Tests

• test/openclaw-paths.test.mjs: precedence and blank-variable handling.
• test/mdmirror-workspace-map-entries.test.mjs: entries form, list form, OPENCLAW_CONFIG_PATH fallback, state-dir fallback, state-dir-rooted and home-rooted defaults.
• Both are registered in the npm test chain and in scripts/ci-test-manifest.mjs (core-regression). Full suite, core-regression, cli-smoke, packaging-and-workflow and verify-package-runtime are green locally; dist is rebuilt and committed.

Verification on a live install

Running as a hotfix on a seven-agent OpenClaw 2026.9.2 install: the startup log went from mdMirror: no agent workspaces found to mdMirror: resolved 7 agent workspace(s), and mirror files land in each agent's own workspace.

[gorkem2020]

Ready for review. Rebased onto the current master (93899f88, post #946); only the two test-registration files conflicted (ordered union), the source is unchanged from the draft.

Fleet evidence: the mirror half (per-agent workspace map from agents.entries) has run on our gateway since 2026-09-06 and the shared state-dir resolver since the 2026-09-12 cut; every agent's markdown mirror lands in its own workspace and the CLI resolves the same paths as the runtime. npm run build and the full npm test chain pass on the rebased head.