docs: code comments name the headings README has now (closes #724)

The README rewrite renamed or merged several headings that comments still
cited. Each comment now names the current heading. Line number citations of
README become headings too, and one test name drops its line numbers.

The e2e workflow's citations of "In CI" are dropped, because no section has what
they pointed at. Its comment also corrects what it says about required jobs and
open reports.

The comment on withLock() no longer states a Firefox private window exception,
because the manifest keeps the extension out of those windows.

Two comments also take corrections from reviews: the cases with no total in
DeleteAddress's warning, and the screens that say a swap's amount could not be
decoded.

Model: opus-5-5

src/popup/views/helpers.js

@@ -272,7 +272,7 @@ function clearFlash() {
 }
 
 // The flash line reserves exactly one line, and a message that wrapped would
-// push the screen below it down (README, No Layout Shift). So #flash-msg never
+// push the screen below it down (README, Appearance). So #flash-msg never
 // wraps: text too long for the line is cut with an ellipsis, and the whole
 // message is also put in the line's title. Write messages to fit, at most 50
 // characters, so none is cut.
@@ -528,9 +528,9 @@ const ADDRESS_MIN_DISPLAY_LEN = 32;
 
 // Truncate the middle of a string, replacing removed characters with "…".
 // Safety: refuses to truncate more than 10 characters, which is the maximum
-// that still prevents address spoofing attacks (see Display Consistency in
-// README).  Callers that need to display less should use a different UI
-// approach rather than silently making addresses insecure.
+// that still prevents address spoofing attacks (see Addresses in README).
+// Callers that need to display less should use a different UI approach rather
+// than silently making addresses insecure.
 function truncateMiddle(str, maxLen) {
     if (str.length <= maxLen) return str;
     const removed = str.length - maxLen + 1; // +1 for the ellipsis char
@@ -633,9 +633,9 @@ function formatAddressHtml(address, ensName, maxLen, title) {
     return renderAddressHtml(address, { title, ensName, maxLen });
 }
 
-// A transaction's time as every screen shows it (README, Display
-// Consistency): the ISO datetime, in UTC when the UTC Timestamps setting is
-// on, and the relative age. Views import these two; they keep no copies.
+// A transaction's time as every screen shows it (README, Amounts): the ISO
+// datetime, in UTC when the UTC Timestamps setting is on, and the relative age.
+// Views import these two; they keep no copies.
 function isoDate(timestamp) {
     const d = new Date(timestamp * 1000);
     const pad = (n) => String(n).padStart(2, "0");