Codex/misc fixes

[NateEaton]

Summary

This PR follows up on the v0.11.0 reader/background-theme work with a set of user-facing fixes and refinements. It addresses a release-only navigation regression, improves the labels multi-select flow, redesigns and expands the reader typography sheet, restores dynamic accent behavior for non-Sepia reader themes, and fixes reader search navigation so matches reliably scroll into view. Also recovered a lost design spec.

What This Fixes

Navigation drawer

• Fixes a release-only regression where the navigation drawer could be opened but would not dismiss by tapping outside it or swiping it closed.
• This only affected minified release builds; debug installs behaved correctly.

Labels multi-select sheet

• Clears the label search field whether the user selects an existing label with the keyboard action or by tapping the search result.
• Keeps selected labels pinned directly below the search field so they remain visible while continuing to choose more labels.
• Improves the add/edit labels flow in bookmark creation and related entry points.

Reader typography sheet

• Adds direct reader-theme selection from the sheet, including switching the app theme when needed and remembering the last light and dark reader appearances separately.
• Reorganizes the typography/settings sheet into Text, Layout, and Theme tabs.
• Splits controls into clearer groups:
  • Text: font, font size, line spacing
  • Layout: width, justification, hyphenation
  • Theme: Paper, Sepia, Dark, Black
• Moves reset actions out of the main settings list and into low-emphasis footer actions:
  • Reset text
  • Reset layout
  • Reset theme
• Updates width presets to N / M / W = 75% / 85% / 95%.
• Improves the visual treatment of selections and theme previews for better consistency with the rest of the app.

Reader theming and accents

• Restores dynamic Material You accent behavior for Paper, Dark, and Black on supported Android versions.
• Preserves the curated background/surface work introduced in v0.11.0 rather than reverting to fully dynamic themes.
• Keeps Sepia fully curated.
• Updates reader template styling so links, buttons, rules, and related accent elements no longer rely on hard-coded blue/white values.
• Makes links easier to identify in every reader theme by using subtle underlines consistently.

Reader search navigation

• Fixes the reader search behavior where searching from mid-article could leave the highlighted result off-screen.
• Fixes next/previous result navigation so the reader now scrolls reliably to matches instead of only moving once a result happens to be in or below the current visible area.
• Improves the overall usability of in-article search in long articles.

Duplicate URL Detection spec

• Recreated and committed document missed in commits for v0.11.0
• It documents an approach for detecting when a new bookmark being added has a URL that matches an existing bookmark, giving the user information to make a decision on whether to add again or not.

Additional reader and delete fixes

• Fixes rapid multi-delete behavior in bookmark lists so each undo snackbar stays tied to the correct bookmark and pending deletes remain visibly disabled until confirmed or undone.
• Alters the delete snackbar label to reference the bookmark title (fragment)
• Fixes reader width behavior so changing width no longer unintentionally changes the effective text size on smaller screens.
• Makes reader theme changes apply in place, reducing visible reload/jump behavior when switching between Paper, Sepia, Dark, and Black.
• Expands the Wide text width preset from 95% to 98%.
• Refines fullscreen video controls so the exit and rotate pills stay properly positioned across phone and tablet portrait/landscape layouts.

Documentation and polish

• Updates the English user guide to reflect the drawer, labels, reader settings, theming, and search behavior changes.
• Updates localized strings needed for the new sheet structure and controls.