docs(man): backfill man pages with wiki-only info (source-of-truth pass)

Port information that previously lived only in the GitHub wiki into the
authoritative scdoc man pages, so the man pages become the single source
of truth for module documentation.

33 man pages enriched (options, format replacements, actions, style
selectors, troubleshooting and implementation notes). Additions were
verified against the source; stale/incorrect wiki entries were
deliberately not ported. All pages still compile with scdoc.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

man/waybar-clock.5.scd

@@ -6,7 +6,16 @@ waybar - clock module
 
 # DESCRIPTION
 
-*clock* module displays current date and time
+*clock* module displays current date and time.
+
+There are two implementations:
+
+- *clock*: Full-featured implementation, including the calendar and timezone
+  support described below. Enabled at build time when either C++20 concepts
+  (\_\_cpp\_concepts >= 201907, gcc >= 13) are available, or the HowardHinnant date
+  library <https://github.com/HowardHinnant/date> is installed.
+- *simpleclock*: Fallback that provides date and time display only. Used when the
+  above build conditions are not met.
 
 # FILES
 
@@ -27,7 +36,8 @@ $XDG_CONFIG_HOME/waybar/config ++
 |[ *format*
 :[ string
 :[ *{:%H:%M}*
-:[ The format, how the date and time should be displayed. See format options below
+:[ The format, how the date and time should be displayed. See format options
+   below. Split the braces to insert literal text, e.g. *{0:%H}text{0:%M}*
 |[ *timezone*
 :[ string
 :[
@@ -295,6 +305,11 @@ View all valid format options in *strftime(3)* or have a look https://en.cpprefe
 
 - *#clock*
 
+If displaying seconds causes other modules to shift side to side, the cause is
+usually proportional-width digits. If your font supports it, add
+*font-feature-settings: "tnum";* to the *#clock* style (or wherever you set the bar
+font) to use fixed-width numbers.
+
 The following classes are used only inside the *{calendar}* tooltip. Their
 foreground *color* is read and applied to the corresponding calendar cells in
 the tooltip markup:
@@ -313,6 +328,10 @@ name not valid error message try one of the following:
 - check if LC_TIME is set properly (glibc)
 - set locale to C in the config file (musl)
 
+When using *clock* instead of *simpleclock*, the locale defaults to *C* regardless
+of the locale settings. To override this, prepend *L* to the format string, e.g.
+*{:%a %m %d}* becomes *{:L%a %m %d}*.
+
 The locale option must be set for {calendar} to use the correct start-of-week, regardless of system locale.
 
 ## Calendar in Chinese. Alignment