gosalyn: row 230 BUILD.md, what ships, six deviations for review (sage-1570), tests and singles

agents/gosalyn/work/queue-230/BUILD.md

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+# Row 230: C2-13a unit render and host precheck
+
+Gitea #1732. Vikunja #416 (track T2). Brief: docs/plans/2026-10-20_case2-rows.md, section "C2-13a",
+blob f6b4933f0f47 (01b40d357, sage-1562). Base: 00d4cc1f6 (row 190). Reviewer: Webby. Gate: the cli
+suite plus every scripts/test-*.sh.
+
+## What ships
+
+`scripts/case2-unit.sh` renders `[email protected]` and `mosaic-webui.service` from the two existing
+templates into the system unit directory, for the default instance only. It writes each unit through
+a temp file at mode 0644, runs `daemon-reload`, enables both units, starts the bus and then the
+Console. If the bus fails to start, the script refuses and leaves the Console unstarted. Both units
+get `WantedBy=multi-user.target`, and neither gets `After=` or `Wants=`. The script never links a unit
+file into place. A re-install refuses unless each installed unit passes the same checks, both units
+name one copy, and each equals the render apart from the copy id.
+
+`--profile library` (the default) refuses `--pm`, `--claude`, `--tester-port` and `--sso`, and needs
+the preview proxy flags plus the proof pair. `--profile factory` refuses the six proxy flags and takes
+`--pm` and `--claude`. Both refuse `--checkout` and `--board`.
+
+`scripts/case2-precheck.sh --business ID [--profile factory|library]` runs as `<user>`. It prints one
+`ok` or `REFUSED` line per check and exits 1 if any check refused. It prints variable names only,
+never values.
+
+`packages/cli/README.md:713` now says nothing creates the session env file, only the Case 2 precheck
+reads it, and the precheck prints only variable names (webby-0034 N2, webby-0035).
+
+## Deviations for review
+
+Sage accepted all six for the build (sage-1570). Webby rules on each.
+
+1. The precheck takes `--business ID`. The brief names no other way to find the business file.
+2. A run root `<dataRoot>/launches/<business>` that doesn't exist passes, with a note that the first
+   launch creates it at 0700 (session.mjs:47 and newRun). A symlink refuses, and so does an existing
+   entry that isn't a 0700 directory.
+3. The claude marker check passes when the reply holds the marker and input plus cache tokens are at
+   most 2000. **The 2000 ceiling is unmeasured.** The tests use fakes at 40 and 9000 tokens. Measuring
+   it on a real claude belongs to row 195's install run, not this row.
+4. A non-root test can't create a root-owned proof file. For the "proof not owned by the user" case,
+   the fake getent reports another uid for the user, so the user's own file reads as someone else's.
+5. The unit script refuses `%h` left in any unit, rendered or installed. A system unit expands `%h`
+   to root's home. The render replaces every `%h`, so the test edits an installed unit to reach it.
+6. With `--auth-header X-Authentik-Uid`, the allowed user must be 64 lower-case hex characters (lead
+   decision 101). The test covers both the refusal and the pass.
+
+## Tests (packages/cli/tests/case2-unit.test.mjs, 28 cases)
+
+The tests use a scratch unit directory and a scratch home, plus fake systemctl, getent, sudo, id,
+node, bwrap and claude. They never touch /etc/systemd, ~/.mosaic-dev, ~/.config/mosaic-dev or a
+live unit. Every precheck case asserts its output doesn't hold the fixture key.
+
+- Unit: the clean library render, PATH for a node outside the default list and for /usr/bin/node, the
+  systemctl order, a failed bus start, no `systemctl link`, factory `--pm` and `--claude` rendered and
+  absent, re-install to another copy, edits to an installed unit, template restrictions,
+  EnvironmentFile placement, unknown tokens, PermissionsStartOnly and `+`/`-+` Exec prefixes,
+  symlinked unit paths, bad `--node`, re-install drift, a split copy pair, bad copy ids, every library
+  and factory flag refusal, and bad `--claude`.
+- Precheck: a good host, node older than 24, more than one group, sudo succeeding, XDG_DATA_HOME,
+  HOME mismatch, a run root mode, a bad config, bwrap failing, the port floor at or below the Console
+  port, a missing Console unit, bus.tester per profile, profile-library-business, the claude check
+  (no route, replaces, appends, missing, the unit's MOSAIC_CLAUDE_BIN beating PATH), and the session
+  env file (missing, 0644, symlink, empty, emptied by a later line, quoted).
+- Bind (mos-1100): inside `binds()` plus `sandboxArgv()`, a bind on port 980 gets EACCES, and a bind
+  on a free port of 1024 or above succeeds. The test fails if the host's floor is at or below 980.
+
+## Verification
+
+Singles, run before the gate: case2-unit.test.mjs passes 28/28 with no skips, and host.test.mjs (it
+reads the cli README) passes 42/42. No test pins a hash of the README. No other test reads the two
+scripts.