feat(telemetry): session-telemetry seam with mandatory redaction + OTel backend

Revive the reviewed session-telemetry packages from the closed
session-telemetry-otlp-rfc branch (PR #222/#231) on current master, renamed
to @deepseek-ai/dsh-session-telemetry{,-otel} (the SDK component-telemetry
package holds the dsh-telemetry name).

Delta over the branch version: every record now passes a telemetry/redact
waterfall between projection and emit() — the innermost next() applies a
non-configurable conservative credential-shape rule set, listeners stack
stricter rules, a throwing rule withholds the record fail-closed, and the
canonical log is never rewritten. This answers the export-side concern that
closed PR #222; the boundary axiom (our aspect ends at emit(); delivery is
the reporting SDK's) is unchanged, and the runtime-telemetry RFC's outbox /
readCommitted lane is recorded as deferred in the Agent Note.

Covered by seam/redact/OTel-wire unit tiers (100% per-file) and a keyless
Loader-composition e2e that boots the examples fixture against a mock OTLP
collector and pins redaction on the wire plus the untouched canonical log.

knip.json

@@ -31,6 +31,7 @@
         "headless-agent/tests/fixtures/goal-domain/seed-goal.ts",
         "headless-agent/tests/fixtures/time-context-driver.ts",
         "headless-agent/tests/fixtures/time-context-mock-llm.ts",
+        "headless-agent/tests/fixtures/telemetry-otel-driver.ts",
         "acp-agent/tests/snapshots/lsp-definition/workspace/subject.ts",
         "tui-agent/tests/fixtures/tui-scripted-llm.ts",
         "acp-agent/tests/fixtures/subagent/subagent-acp/mock-delegating-llm.ts",
@@ -188,6 +189,16 @@
         "tests/**/*.ts"
       ]
     },
+    "packages/telemetry/session-telemetry-otel": {
+      "entry": [
+        "tests/**/*.spec.ts",
+        "tests/**/*.e2e.ts"
+      ],
+      "project": [
+        "src/**/*.ts",
+        "tests/**/*.ts"
+      ]
+    },
     "packages/util/brand": {
       "project": [
         "src/**/*.ts"