fix(plugins): stamp surface identity at record time, not send time

Six defects in 0.3.x plugin telemetry. Defects 1, 2 and 6 were not three bugs:
they were one spool protocol getting three properties wrong.

Identity was decided by the wrong process. `harness` was stamped in record(),
correctly, but `source` was read from a module global in flush() — so whichever
process drained the spool named every event in it. Two processes never call
init(): mcp_server.py, and the detached `python3 telemetry.py` sender that
spawn_flush() starts. record() now stamps source beside harness, and the build
generates core/_harness_id.py per host so identity resolves with no init() call
at all. That also unifies two defaults that disagreed (`<host>_plugin` vs
`MEM0_<HOST>_PLUGIN`), which could yield three source values for one plugin.

Ownership was inferred, not held. Path.replace is os.rename, which preserves
mtime, so a claim made after a quiet minute inherited the spool's age and was
stealable the instant it existed. Claims are touched on creation and the
per-batch rewrite doubles as a lease heartbeat.

Progress was not durable. flush() returned on the first failed batch without
truncating, so the retry re-posted from index 0 — 150 events delivered 250
times. It now rewrites the claim with the unsent remainder after every batch,
bounding a crash to one repeated batch, and each event carries a uuid.

Parked batches starved. They were only reachable when no spool existed, and
because sessions keep recording there usually was one, so a batch parked by a
failed send waited until the 7-day expiry deleted it unsent — despite its own
presence being what starts the sender. flush() drains them in the same run, and
expiry now applies only after a genuine retry has failed.

code.install counted upgrades and repeat sessions. is_first_run() read the
identity file, which only a successful flush writes, so an offline user recorded
an install every session forever. A dedicated install-state.json is claimed
atomically at record time; a non-empty data directory reads as an upgrade.

The docs called this anonymous. Every event carries the account email, and the
hashes were unsalted SHA-256 over a git remote URL or an absolute path
containing the username. READMEs, the module docstring and a new docs section
now say what the code does, and repo/session digests are salted per install.

A cached email outlived an API key change. It is now re-resolved when the key's
fingerprint differs, and $identify aliases anonymous->email only — aliasing one
account to another merges person profiles irreversibly.

All six shipped green because the shared core's only tests lived under one host,
behind a conftest that calls init() at import. Core behaviour was never
exercised uninitialised. Adds agent-plugin-core/tests with no init, including
subprocess tests and coverage for the portable plugin, which has no flush worker
and would pass a native-only test vacuously.

Also puts the three surface headers on the SDKs, CLIs and integrations, and
corrects a README claiming ZAPIER/STRANDS were already in the platform allowlist.

Verified: 59 core tests, 203 claude-code, 11 cursor, 5 codex, 2 kimi, 6
antigravity. ruff and compileall clean. --check clean for all six hosts.
TypeScript changes are not typechecked locally (deps not installed).

Claude-Session: https://claude.ai/code/session_01C7tEmH86HAr7GoAAKCEHZb

integrations/claude-code-plugin/tests/test_telemetry.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import json
+import os
 import sys
 from pathlib import Path
 from unittest.mock import patch
@@ -198,9 +199,11 @@ def test_a_stale_claim_is_reclaimed(isolated_env, monkeypatch):
     telemetry.record("search")
     orphan = telemetry._claim_spool()
     assert orphan is not None
-    monkeypatch.setattr(
-        telemetry.time, "time", lambda: orphan.stat().st_mtime + telemetry.CLAIM_STALE_SECONDS + 1
-    )
+    # Frozen rather than re-stat'd per call: flush() drains the live spool and
+    # then looks for parked claims in the same run, so by the second look this
+    # file no longer exists.
+    stale_now = orphan.stat().st_mtime + telemetry.CLAIM_STALE_SECONDS + 1
+    monkeypatch.setattr(telemetry.time, "time", lambda: stale_now)
 
     with patch.object(telemetry, "_post", lambda payload, url: True):
         assert telemetry.flush() == 1
@@ -210,9 +213,13 @@ def test_an_expired_claim_is_dropped(isolated_env, monkeypatch):
     telemetry.record("search")
     orphan = telemetry._claim_spool()
     assert orphan is not None
-    monkeypatch.setattr(
-        telemetry.time, "time", lambda: orphan.stat().st_mtime + telemetry.CLAIM_EXPIRY_SECONDS + 1
-    )
+    expired_now = orphan.stat().st_mtime + telemetry.CLAIM_EXPIRY_SECONDS + 1
+    monkeypatch.setattr(telemetry.time, "time", lambda: expired_now)
+    # Expiry now only discards a batch that was genuinely retried and failed,
+    # so age alone is not enough — age it past the attempt budget too.
+    retried = orphan.parent / orphan.name.replace("-a0.", f"-a{telemetry.MAX_CLAIM_ATTEMPTS}.")
+    orphan.replace(retried)
+    os.utime(retried, (expired_now, expired_now - telemetry.CLAIM_EXPIRY_SECONDS - 1))
     assert telemetry._claim_spool() is None
     assert not list(memory_core.data_dir().glob("telemetry-*.sending"))
 
@@ -258,12 +265,47 @@ def test_an_unresolvable_key_falls_back_to_the_anonymous_id(isolated_env, monkey
     assert telemetry.resolve_distinct_id()[0].startswith("code-anon-")
 
 
-def test_is_first_run_flips_after_the_first_identity_write(isolated_env):
+def test_first_run_is_not_flipped_by_writing_the_identity_file(isolated_env):
+    """The identity file is written by a successful flush, not by recording.
+
+    Keying first-run off it meant an offline user recorded code.install on every
+    session forever, and every 0.2.x user recorded one on their first 0.3.x run.
+    """
     assert telemetry.is_first_run()
     telemetry.anonymous_id()
+    assert telemetry.is_first_run()
+
+
+def test_claiming_install_ends_first_run(isolated_env):
+    assert telemetry.claim_install() == "install"
     assert not telemetry.is_first_run()
 
 
+def test_install_can_only_be_claimed_once(isolated_env):
+    """Two sessions starting together must not both record an install."""
+    assert telemetry.claim_install() == "install"
+    assert telemetry.claim_install() is None
+
+
+def test_a_populated_data_dir_reads_as_an_upgrade(isolated_env):
+    """A fresh install has an empty data directory; anything else predates it."""
+    data_dir = memory_core.data_dir()
+    data_dir.mkdir(parents=True, exist_ok=True)
+    (data_dir / "requirements.txt").write_text("mem0ai\n", encoding="utf-8")
+    assert telemetry.claim_install() == "upgrade"
+
+
+def test_a_version_change_is_claimed_once(isolated_env):
+    telemetry.claim_install()
+    state_path = memory_core.data_dir() / "install-state.json"
+    state = json.loads(state_path.read_text())
+    state["plugin_version"] = "0.0.1-old"
+    state_path.write_text(json.dumps(state), encoding="utf-8")
+
+    assert telemetry.claim_version_change() == "0.0.1-old"
+    assert telemetry.claim_version_change() is None
+
+
 def test_spawn_flush_does_nothing_without_a_spool(isolated_env):
     with patch.object(telemetry.subprocess, "Popen") as popen:
         assert telemetry.spawn_flush() is False