feat: each app's own colour, errors a true red, part of Halkyon Days (ADR 0045, D18, D19)

halkyone_ui's theme takes the app's own colour as its primary
(AppPrimary, appTheme(primary:)): Halkyon, Train and Meditate cobalt as
before, Myrmex strawberry once it asks for it. Filled and floating
buttons fill with its deep shade in both modes, white on it, and the
first start and the operator's screen wash in it. Errors become a true
red in every app, #B3261E light and #FF6B5E dark, far in hue from
Myrmex's strawberry, which Material's crimson stood beside (D19).

An app with a name of its own shows it alone in its wordmark, in its
colour (BrandWordmark.alone, LaunchScreen.alone, AppFrame.productAlone).
About says the app is part of Halkyon Days, as does the foot of the
instance's pages: profiles, privacy, invitations (D1). A secret's file
keeps an instance's domain whole where the app is named as it
(halkyon.li, not li).

ADR 0045 records D18 and D19, the names step 4 keeps, and step 3 built.

Whats-New: Errors show in a clearer red, and About says the app is part of Halkyon Days.
Whats-New-De: Fehler erscheinen in einem klareren Rot, und „Über“ nennt Halkyon Days, zu dem die App gehört.
Signed-off-by: Tizian 「ティツィアーン」 <c.3a8bz@simplelogin.com>
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

docs/adr/0045-halkyon-days.md

@@ -8,13 +8,20 @@
   same day by the developer: step 2 waits until halkyon.li opens to the public, which
   also moves it off the host at home (an open question below); the snap names
   `halkyon` and `myrmex` are registered, the Snap Store account's publisher named
-  Halkyon Days (`halkyon-days`).
+  Halkyon Days (`halkyon-days`). Step 3 built 13 Nov 2026. Amended on 13 Nov 2026
+  by the developer for step 4: D18 and D19 (the agent's recommendations, which they
+  chose), and the names step 4 keeps: Train and Meditate stay "Halkyon Train" and
+  "Halkyon Meditate" for now, "Halkyon" over their word in their wordmark, cobalt over
+  copper; the Proton Pass items of Halkyon's and Myrmex's keystores renamed by the
+  developer after the apps (`Halkyon – Android release keystore`, `Myrmex – …`), as
+  the release tool finds an app's item by its name.
 - **Builds on:** ADR 0015 (one repository), ADR 0016 (one account across an instance),
   ADR 0017 (a password and an authenticator), ADR 0020 (SimpleLogin), ADR 0031 (the
   apps' icons), ADR 0039 (halkyon.li at home).
 - **Amends:** ADR 0039, whose halkyon.li was the family's instance alone (D6); ADR
   0016, for Halkyon and Myrmex (D7); ADR 0020, whose SimpleLogin goes out of use (D8);
-  ADR 0031, D3, D6 and D11, for Halkyon's icon (D14).
+  ADR 0031, D3, D6 and D11, for Halkyon's icon (D14); halkyone_ui's theme, every
+  app's around cobalt (D18, D19).
 
 ## Context
 
@@ -160,6 +167,29 @@ gives people calm from prying, surveillance-capitalist eyes.
   `halkyon-learn` and `halkyon-todo` are closed, their one user moving over. Both
   registered 12 Nov 2026 under the account that publishes the others, its publisher
   shown as Halkyon Days.
+- **D18 Each app has a colour of its own, Myrmex strawberry** (the agent's
+  recommendation, which the developer chose on 13 Nov 2026): an app with a name of its
+  own shows that name alone in its wordmark, in its own colour, Halkyon in cobalt and
+  Myrmex in strawberry (`BrandWordmark.alone`, `AppFrame.productAlone`), where Train and
+  Meditate keep "Halkyon" over their word. The colour is the theme's primary role
+  (halkyone_ui's `AppPrimary`, `appTheme(primary:)`): buttons, links, switches, the
+  add and voice buttons, filled buttons and the first start's wash; neutrals, slate
+  blue and copper stay every app's. Myrmex's strawberry is deeper than the palette's
+  (#EC3E7C, too light for white on it or as text on white): #C21E5C, white on it at
+  5.8:1, the fill in both modes as cobalt's deep shade is; #FFB1C9 its text and marks
+  in dark mode; containers #FFD9E3 on #3F0018 light and #5C1130 under #FFD9E3 dark.
+  Halkyon, Train and Meditate keep cobalt. Alternatives were the palette's strawberry
+  as it is (too light for text, 3.6:1), a darker berry nearer purple (losing the
+  strawberry), and cobalt for every app with strawberry only on the navigation bar, as
+  before (the developer wanted Myrmex's own colour on its buttons).
+- **D19 Errors are a true red in every app** (the agent's recommendation after looking
+  at Proton's apps, which the developer chose on 13 Nov 2026): Myrmex's strawberry
+  would be read as an error beside Material's default error colour, a crimson; so
+  every app, Halkyon too, takes a red far from it in hue: #B3261E light, white on it,
+  container #F9DEDC with #410E0B; dark #FF6B5E, saturated rather than Material's pastel
+  #FFB4AB, with #3B0905 on it, container #5C1712 with #FFDAD5. Proton's apps keep
+  strong reds in their dark themes too (Mail's #F5385A, Wallet's #FB7878), but theirs
+  are crimson (349°), 12° from our strawberry (337°); ours sits at 3°.
 
 ## Steps
 
@@ -185,7 +215,8 @@ gives people calm from prying, surveillance-capitalist eyes.
    configuration, tags and history; the migrations' module names (D11).
 4. **The names people see** (D2, D3, D14): Halkyon's and Myrmex's texts, the launcher's
    labels, windows, mails, the privacy and profile pages, the listings; Halkyon's
-   kingfisher icon; "part of Halkyon Days" in About.
+   kingfisher icon; "part of Halkyon Days" in About. Built 13 Nov 2026 with D18 and
+   D19, "part of Halkyon Days" at the foot of the instances' pages too.
 5. **The deploy** (D7, D9, D13, D15, D16): the variables and compose files renamed;
    Myrmex, Train and Meditate on registers of their own, the developer's account copied
    into Myrmex's (and Train's and Meditate's, as their data is named by it too);