docs: convert the user guide to the house style

[brickbots]

Full simplified technical English pass over docs/source/user_guide.rst, using the docs skill's seven rules and approved-term table. Part of the manual-wide conversion, one PR per file.

Measured change

  PASS  docs/source/user_guide.rst
     em-dash 99->0 | semicolon 30->0 | banned 55->20 | words 8514->8491 (-0%)
     terms: choose 17->1, pick 5->0, the display 2->0, the unit 6->1, the device 1->0, target 13->9, DSO 5->3
OVERALL: PASS

What the converting agent reported

EM_DASHES: 99 -> 0    (baseline was 99, not the 93 in the brief)
SEMICOLONS: 30 -> 0
TERMS: choose/choosing->select x12; pick->select x4; activates->selects;
  scope->telescope x18 (4 survivors are "polar scope", an approved fixed
  compound); the unit/the device->the PiFinder x6; display->screen/show x4;
  "switched off"->"turned off" x2; boot/booting->starts up x2;
  "back out"/"return to"->"go back" x4; "Holding X"->"press and hold X" plus 9
  further gesture normalisations, with the "Hold SQUARE and press +" chord left
  intact; "Pressing X brings up Y"->"Press X to open Y" x8;
  option->menu item x5 where the row was meant; DSO->deep-sky object x2 (the
  on-screen labels DSO Display / DSO... kept); "live target"->"live readout" in
  Polar Align, to avoid the object sense
STRUCTURAL: ~110 sentence splits, no procedure or step reordered. The IMU gloss
  lifted out of parentheses into its own sentence. The CSV row-resolution
  sentence split into five. Polar Align step 1 re-led with its command verb,
  same instruction and order. "And the magnitude and size..." (opened with a
  conjunction) rewritten.
LEFT_ALONE: all heading text, underlines and levels; "polar scope" x4; the
  on-screen DSO labels; "browse" x3 (the sense is looking through objects, not
  moving within a menu); the page's existing +/- and UP/DOWN key notation,
  since changing it would churn 12 lines for no rule; contractions; en-dashes
  in numeric ranges (7-10 deg, 0-360) and the U+2212 minus signs in the
  Contrast Reserve table; the rev4-default / v3-in-a-note convention.
FACT_CONCERNS:
  1. CROSS-PR ITEM. The key list under "The Menu System" carries an in-file
     comment saying it is duplicated in quick_start.rst and must be kept in
     sync. This pass converted it here (activates->selects, Holding->Press and
     hold), and the quick_start agent independently converted its own copy.
     The two must be reconciled before both PRs merge.
  2. "The Focus screen above offers HELP and Exposure" points at
     images/user_guide/quick_menu_00.png, introduced two lines earlier as the
     generic Quick Menu shot. If that image is not the Focus screen, the
     sentence is stale.
  3. The paragraph that began "And the magnitude and size..." had no explicit
     trigger; rendered as "The next press shows...", inferring it continues the
     SQUARE cycle described two paragraphs up. Worth a maintainer glance.
  4. Battery life said "the display sleep turned off"; written as "the screen
     sleep" for term consistency, but the real menu item appears to be Sleep
     Time under User Preferences.
  5. "images of every object in its catalog" - singular where the manual
     elsewhere says catalogs. Left as a fact.

Content changes (added after review)

• "images of every object in its catalog" overstated what ships.
  astro_data/pifinder_objects.db holds 149,329 objects, of which 134,158 are
  double stars, 742 single stars and 90 triples. The non-stellar remainder is
  13,758, which matches software.rst's "13,000+ images" almost exactly: the
  image set covers the extended objects, not the star catalogs. The sentence now
  reads "images of all the extended objects in its catalogs", which also fixes
  the singular "catalog" flagged in FACT_CONCERNS.

• Two escapes from the unit -> PiFinder rule. "appears on those units too"
  and "New units often ship a version or two behind" are now "PiFinders".

• Two dead click-to-enlarge links. Same defect as build_guide: Sphinx
  emits a :target: value verbatim as an href, so a source-tree path 404s. The
  two CATALOG_images screenshots pointed at ../../images/screenshots/.
  Audited the built HTML: 5 of 7 targets resolved before, 7 of 7 after. The
  other five already used the _images/ form.

Safety

Every other change in this PR is style only. No numbers, procedures or step order were changed.

Verified mechanically against origin/main that every heading (text and underline character), every :ref:, :doc:, image path, substitution, include:: and external URL is unchanged. Headings matter because autosectionlabel turns each one into a cross-reference target that other pages depend on, and a rename would break them silently.

Sphinx builds clean under -n (nitpicky).

Any FACT_CONCERNS above that are not listed under Content changes were deliberately not fixed. They are reported for a maintainer decision, since changing them would be a content edit rather than a style one.

🤖 Generated with Claude Code

https://claude.ai/code/session_01HqTCarGCgTRWBQ1ysG8XFD