Phase 7: authored assets (diagrams, code exhibits, client wall, budget)

Phase 7 is mostly authored assets. This commit is the asset half; the
template half is a Builder child issue because this phase must not write
application code.

DoD items satisfied or advanced:

- [x] Eight diagrams present, both themes, readable at 1x and on mobile
      8 SVGs, one byte-identical <style> block across all 8 (one visual
      language by construction). Light and dark resolve from a single file
      via prefers-color-scheme, verified per file in Chrome: 8/8 return two
      distinct palettes. Geometry verified with getBBox(), not estimated:
      0 findings after fixing 74 (text overflow, partial overlap, empty
      text, out-of-viewBox). Mobile type at the 900px minimum is 14.1/12.2px.

- [x] Six code exhibits with a two-sentence rationale each
      212 verbatim lines across five eras, copied with cp/sed from the
      read-only archive. Every rationale is exactly two sentences about why
      the code is good; every exhibit also carries an honest_note, and where
      the code is not good the note says so (the 3,400-line procedural PHP
      script is presented for its operational judgement, not its structure).

- [~] Every image optimised; total page weight budgeted and recorded
      BUDGET.md records measured raw and gzip weights for all 15 served
      files: 63,802 B raw / 13,220 B gzipped. Zero rasters by design. Page
      weight of a real page is not measurable until Phase 2 templates and
      Phase 3 serving exist, and is recorded as open rather than asserted.

- [x] Archive never linked or exposed
      No mount paths or volume names under content/. Provenance recorded as
      "private archive, path withheld".

- [ ] Client wall reads as deliberate  -> needs markup/CSS (Builder)
- [ ] Lighthouse held at >= 95/95      -> needs a served page (Phase 3)

Also: the client wall is authored as data (45 entries, 44 distinct names) with
the 45-vs-46 discrepancy and the Diajio -> Diageo correction recorded
rather than papered over. No commercial marks are enabled: that is a
permission decision for Sam, so availability is recorded and permission is not
implied.

content/assets/README.md

@@ -0,0 +1,73 @@
+# content/assets — authored exhibits
+
+Everything the site shows that is not Markdown prose. Authored in Phase 7; wired
+into templates by Phase 2's builder.
+
+```
+content/assets/
+├── BUDGET.md              measured weights for every asset, and the budget
+├── VERIFY.md              what was checked, with the output pasted in
+├── diagrams/              8 SVGs, light and dark in one file each
+│   ├── README.md          the visual language and the presentation contract
+│   └── manifest.yaml      id, area, level, title, alt text per diagram
+├── code/                  6 verbatim excerpts, 212 lines, 5 eras
+│   ├── README.md          the rules these follow
+│   └── manifest.yaml      era, language, shows, rationale, honest note
+└── logos/
+    └── clients.yaml       the client wall: 45 entries, 44 distinct names
+```
+
+## Three decisions worth knowing
+
+**The client wall is type, not logos.** Forty-five names in one typeface at one
+size on an even grid. Nothing is an image, so nothing can break, and no client is
+visually ranked above another. Ten client marks do exist in Simple Icons; none is
+enabled, because using a company's mark on a public portfolio is a permission
+question for Sam, not a design choice for an agent.
+
+**Diagrams carry both themes in one file.** Not two files that can drift: one
+`<style>` block with the light palette and the same selectors repeated under
+`prefers-color-scheme: dark`. The eight files therefore share one palette by
+construction.
+
+**Code excerpts are copied, never retyped.** Including the defects. An excerpt
+that has been tidied is a claim, not evidence — and this site's whole argument is
+that the claims are checkable.
+
+## What is wired and what is not
+
+| DoD item | State | Evidence |
+|---|---|---|
+| Client wall reads as deliberate, no broken images, no placeholders | **assets done, markup not** | `logos/clients.yaml` — 45 entries, zero image references by design. The grid is CSS and belongs to Builder |
+| Eight diagrams, both themes, readable at 1× and on mobile | **done** | `VERIFY.md` §1–§3: 0 geometry findings, 8/8 resolve two palettes, rendered widths measured |
+| Six code exhibits with a two-sentence rationale each | **done** | `code/manifest.yaml`, `VERIFY.md` §5 |
+| Every image optimised; total weight budgeted and recorded | **assets done, page weight not** | `BUDGET.md`. Zero rasters. A full page cannot be weighed until a page exists |
+| Lighthouse ≥ 95 / 95 after assets | **not measurable yet** | Needs a served page (Phase 3) |
+| Archive never linked or exposed | **done** | `VERIFY.md` §6 — no archive path anywhere under `content/` |
+
+The four "not yet" rows are honest gaps, not omissions: three need a page that
+does not exist until Phase 2 and Phase 3 land, and one needs a live agent console
+from Phase 5.
+
+## Consuming these from templates
+
+```go
+// diagrams: "assets/diagrams/01-homelab-topology.svg"
+<img src="/assets/diagrams/01-homelab-topology.svg"
+     alt="{{ .Alt }}" width="960" height="540" loading="lazy" decoding="async">
+```
+
+The `width`/`height` attributes are not optional — they are what stops the page
+shifting as figures load, which is a Lighthouse CLS and a real annoyance. `alt`
+comes from `manifest.yaml`; if it is set to `""` the SVG's own `<title>`/`<desc>`
+are not read out.
+
+Figures go inside a horizontally scrollable wrapper (`diagrams/README.md`), or a
+960 px schematic becomes 5 px type on a phone.
+
+## Adding an asset
+
+1. Put the file in the right folder; no external references of any kind.
+2. Add an entry to the folder's `manifest.yaml` with `alt` and, for code,
+   `rationale` and `honest_note`.
+3. Re-measure and update `BUDGET.md`. A budget nobody updates is a wish.