feat(obs): nommer chaque requete, et rendre les pages d erreur audibles

OBS-005. Un 500 dans errors.log et les six lignes de app.log qui y menent
n etaient relies que par leur horodatage — ce qui n est pas une relation
des que le serveur traite plus d une requete a la fois. Et un utilisateur
qui dit « ca a plante quand j ai clique sur enregistrer » ne donnait a
personne de quoi chercher.

Chaque requete recoit un identifiant, porte par toutes les lignes de
journal qu elle produit, renvoye en X-Request-Id, et affiche sur la page
500 comme reference a citer.

Il est **genere**, jamais lu depuis un en-tete entrant. Accepter celui du
client serait pratique pour tracer a travers nginx, et permettrait aussi a
n importe qui d ecrire du texte arbitraire — retours a la ligne compris —
dans le fichier de journal. C est ainsi qu un journal cesse d etre une
preuve. Il n y a de toute facon aucun proxy de confiance tant qu OPS-002
est ouvert.

Le test correspondant assure sur l alphabet plutot qu en envoyant un
retour a la ligne : le client de test de Werkzeug refuse d emettre un tel
en-tete, donc l attaque ne peut meme pas etre construite par la, ce qui ne
prouverait rien sur l application.

**Defaut trouve en chemin, et repare.** Les cinq gabarits d erreur
remplissent le bloc `content`, qui n existait que dans la branche
authentifiee de la mise en page. Un visiteur deconnecte tombant sur une
erreur — donc typiquement sur la page de connexion — recevait le logo, le
selecteur de langue, et **aucun message**. Le code de statut etait bon, les
journaux etaient bons, la page etait vide. Le <title> disait quand meme
« 404 », ce qui explique en grande partie que personne ne l ait vu.

Le bloc est desormais rendu dans les deux branches via self.content(),
Jinja refusant deux blocs de meme nom. Un seul cote du if s execute, donc
jamais de double rendu — et c est assure, pas suppose.

550 tests.

app/translations/en/LC_MESSAGES/messages.po

@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: team-tryouts VERSION\n"
 "Report-Msgid-Bugs-To: EMAIL@ADDRESS\n"
-"POT-Creation-Date: 2026-08-11 13:32-0400\n"
+"POT-Creation-Date: 2026-08-11 15:25-0400\n"
 "PO-Revision-Date: 2026-08-07 20:22-0400\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language: en\n"
@@ -20,7 +20,7 @@ msgstr ""
 "Generated-By: Babel 2.18.0\n"
 
 #: app/forms.py:37 app/routes/auth.py:224 app/routes/auth.py:374
-#: app/routes/users/contracts.py:95
+#: app/routes/users/contracts.py:96
 #, python-format
 msgid "%(field)s: %(msg)s"
 msgstr "%(field)s: %(msg)s"
@@ -633,11 +633,11 @@ msgstr "User %(full_name)s created as %(role)s!"
 msgid "Only coaches can manage availability."
 msgstr "Only coaches can manage availability."
 
-#: app/routes/users/contracts.py:83
+#: app/routes/users/contracts.py:84
 msgid "Only presidents, managers, and coaches can upload contracts."
 msgstr "Only presidents, managers, and coaches can upload contracts."
 
-#: app/routes/users/contracts.py:102
+#: app/routes/users/contracts.py:103
 msgid "You do not have permission to upload a contract for this player."
 msgstr "You do not have permission to upload a contract for this player."
 
@@ -650,15 +650,15 @@ msgstr "Contract uploaded successfully for %(username)s!"
 msgid "Only the player can upload their signed contract."
 msgstr "Only the player can upload their signed contract."
 
-#: app/routes/users/contracts.py:176
+#: app/routes/users/contracts.py:175
 msgid "Signed contract uploaded successfully!"
 msgstr "Signed contract uploaded successfully!"
 
-#: app/routes/users/contracts.py:186 app/routes/users/contracts.py:199
+#: app/routes/users/contracts.py:185 app/routes/users/contracts.py:200
 msgid "You do not have permission to download this contract."
 msgstr "You do not have permission to download this contract."
 
-#: app/routes/users/contracts.py:202
+#: app/routes/users/contracts.py:203
 msgid "No signed contract available."
 msgstr "No signed contract available."
 
@@ -881,7 +881,11 @@ msgstr ""
 "Something went wrong on our end. The error has been logged and will be "
 "investigated. Please try again later."
 
-#: app/templates/errors/500.html:12
+#: app/templates/errors/500.html:15
+msgid "Reference to quote if you report this:"
+msgstr "Reference to quote if you report this:"
+
+#: app/templates/errors/500.html:18
 msgid "Try Again"
 msgstr "Try Again"
 
@@ -889,78 +893,78 @@ msgstr "Try Again"
 msgid "Language"
 msgstr "Language"
 
-#: app/templates/layouts/base.html:33 app/templates/layouts/base.html:139
+#: app/templates/layouts/base.html:48 app/templates/layouts/base.html:154
 #: app/templates/pages/dashboard.html:2 app/templates/pages/dashboard.html:3
 msgid "Dashboard"
 msgstr "Dashboard"
 
-#: app/templates/layouts/base.html:39 app/templates/pages/tryouts.html:2
+#: app/templates/layouts/base.html:54 app/templates/pages/tryouts.html:2
 #: app/templates/pages/tryouts.html:3
 msgid "Tryouts"
 msgstr "Tryouts"
 
-#: app/templates/layouts/base.html:45 app/templates/pages/calendar.html:2
+#: app/templates/layouts/base.html:60 app/templates/pages/calendar.html:2
 #: app/templates/pages/calendar.html:3
 msgid "Calendar"
 msgstr "Calendar"
 
-#: app/templates/layouts/base.html:52 app/templates/pages/dashboard.html:43
+#: app/templates/layouts/base.html:67 app/templates/pages/dashboard.html:43
 #: app/templates/pages/evaluations.html:2
 #: app/templates/pages/evaluations.html:3
 msgid "Evaluations"
 msgstr "Evaluations"
 
-#: app/templates/layouts/base.html:60 app/templates/pages/my_teams.html:2
+#: app/templates/layouts/base.html:75 app/templates/pages/my_teams.html:2
 #: app/templates/pages/my_teams.html:3
 msgid "My Team(s)"
 msgstr "My Team(s)"
 
-#: app/templates/layouts/base.html:67
+#: app/templates/layouts/base.html:82
 msgid "Manage Teams"
 msgstr "Manage Teams"
 
-#: app/templates/layouts/base.html:75 app/templates/pages/users.html:2
+#: app/templates/layouts/base.html:90 app/templates/pages/users.html:2
 #: app/templates/pages/users.html:3
 msgid "Manage Users"
 msgstr "Manage Users"
 
-#: app/templates/layouts/base.html:83
+#: app/templates/layouts/base.html:98
 #: app/templates/pages/player_personal_notes.html:2
 #: app/templates/pages/player_personal_notes.html:3
 msgid "My Notes"
 msgstr "My Notes"
 
-#: app/templates/layouts/base.html:91
+#: app/templates/layouts/base.html:106
 msgid "Availability"
 msgstr "Availability"
 
-#: app/templates/layouts/base.html:97
+#: app/templates/layouts/base.html:112
 msgid "Notes & One on One"
 msgstr "Notes & One on One"
 
-#: app/templates/layouts/base.html:104 app/templates/pages/contracts.html:2
+#: app/templates/layouts/base.html:119 app/templates/pages/contracts.html:2
 #: app/templates/pages/contracts.html:3 app/templates/pages/profile.html:9
 msgid "Contracts"
 msgstr "Contracts"
 
-#: app/templates/layouts/base.html:111 app/templates/pages/profile.html:2
+#: app/templates/layouts/base.html:126 app/templates/pages/profile.html:2
 #: app/templates/pages/profile.html:3
 msgid "My Profile"
 msgstr "My Profile"
 
-#: app/templates/layouts/base.html:122
+#: app/templates/layouts/base.html:137
 msgid "Logout"
 msgstr "Logout"
 
-#: app/templates/layouts/base.html:143
+#: app/templates/layouts/base.html:158
 msgid "Toggle dark mode"
 msgstr "Toggle dark mode"
 
-#: app/templates/layouts/base.html:155 app/templates/layouts/base.html:174
+#: app/templates/layouts/base.html:170 app/templates/layouts/base.html:189
 msgid "Dismiss"
 msgstr "Dismiss"
 
-#: app/templates/layouts/base.html:184
+#: app/templates/layouts/base.html:199
 msgid "Team Tryout Management System"
 msgstr "Team Tryout Management System"